Refrigerating apparatus



Sept. 16, 1941. N. J. SMITH REFRIGERATING APPARATUS Filed Feb. 26, 1937 ATTORNEYS.

Fatented Sept. 16, 1941 2,256,127 REFRIGERATIN G APPARATUS Nelson J. Smith,Dayton, Ohio, assignor to Gen eral Motors Corporation, Dayton, Ohio, a corporation of Delaware Application February 26, 1937, Serial No. 127,923

11 Claims.

This invention relates to refrigerating apparatus and more particularly to control means for air conditioning apparatus.

Heretofore, many control devices have been devised which make use of materials which swell or stretch according to changes in humidity, such as wood, paper or hair. These materials, however, do not have fixed characteristics and require delicate adjustment at the time of manufacture, and also require adjustment .during their life because of changes in characteristics.

It is an object of my invention to provide an improved control device which is simple, easy to manufacture, and whose characteristics will not change materially throughout its normal life.

It is a further object of my invention to provide an improved effective temperature control device which is responsive to ambient temperature, relative humidity, air motion, and radiation.

It is a still further object of this invention to provide a control means which may be scientifically set so as to maintain an indoor effective temperature which has a definitev relationship to the outdoor temperature.

It is a further object of this invention to provide a cooling system which may be controlled so as to meet individual requirements.

Another object of this invention is to provide an effective temperature responsive indicating device.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing: 4

Fig. 1 is a view of my improved humidity responsive control means partly in cross section together with a diagrammatic showing of an air conditioning device; and

Fig. 2 is an enlarged detailed view showing the contacts.

It has been found that in many homes, offices and the like the ordinary thermometers and humidostats do not tell a true story of the comfort since they do not take into consideration radiation from the walls and the ceiling, nor do they take into consideration air motion.

In this invention the effective temperature responsive device consists of a mercury-charged capillary tube having a double bulb H at one end thereof. The bulb, as shown in the drawing, is blackened on the exterior so as to absorb radiant heat and has one portion covered by a damp ened wick l3. This device is placed in the room, the air of which is to be conditioned, so as to be exposed to the same radiant heat and air motion to which occupants of the room are normally exposed. This arrangement, therefore, provides a means responsive to dry bulb temperature, humidity, air motion, and radiation.

The length of each section l2 and I3 is chosen so as to make the device responsive as nearly as possible to the effective temperature throughout the normal operating range. A pan of water H is provided below the tube and supplies the wick with water in the usual well-known manner. A plurality of contacts l5 are arranged to extend from within the tube to the outside of the tube and carry enlarged heads on the outside.

The tube is provided with the usual supply of mercury, or the like, iii. A contact ll extends into the tube at a point below the lowermost contact I5. A movable contact 18 is slidably mounted on a contact rod 19 held in position by brackets 20 carried by the tube Ill. The rod [9 and the contact I! are in series with a low-voltage power supply 22 and a relay 23. The relay 0perates a switch, which is in series with the power supply of the air conditioning apparatus, so as to control the same.

' The air conditioning apparatus shown includes a motor 25, a compressor 26 operated thereby, a

condenser 21, and an evaporator 28. The compressor, 26 compresses the refrigerant and forwards the same to the condenser-21 where the "refrigerant is liquefied and collected in a receiver 30 from which the liquid refrigerant is forwarded under the control of a thermostat valve 32 to the evaporator 28 which absorbs heat and, at the same time, condenses moisture out of the air so as to'reduce the humidity.

It is a well-known fact that the indoor temperature should bear a certain relationship to the outdoor temperature so as to eliminate shock resulting from a'change of temperature, such as takes place when one enters-an air conditioned room after having been outdoors. Not all individuals like the same temperature conditions;

and for that reason, it is not always desirable to 1 have the device completely automatic, without any manual adjustment. I have constructed my 'device so as 'to permit one to set the effective to coincide with the top of the mercury II when the effective temperature within' the room isv at 68 degrees and the contacts iii are spaced at one degree intervals and are labeled accordingly, with the result that the uppermost contact, for example, indicates an effective temperature of 76 derecs.- g The American Society of Heating and Ventilating Engineers has made a study of desirable indoor conditions corresponding to various outdoor temperatures and have printed a table in their 1936 Guide, page '13, which indicates what the inside effective temperature should be in certain types of public buildings for various outdoor dry bulb temperatures.

Therod I9 is provided with temperature indications which are placed opposite the contacts 1 i5 for indicating the setting of the contact l8 which should be made for the particular outdoor temperature. Consequently, opposite the lowerperature is 70 degrees, the movable contact l8 should be placed in engagement with the lowermost button l5. Opposite the contact l5 which bears the label 69 is placed the numeral 15, indicating that when the outdoor temperature is 75 the movable contact I8 should register with the stationary contact l5 bearing the number 69.

It is well known that certain people demand a temperature several degrees higher than recommended while others demand lower temperatures than recommended, and for that reason a set screw l9a has been provided whereby the rod l9 may be raised or lowered so as to change the 4. In combination, an enclosure, means for cooling and dehumidifying air for said enclosure, and control means for said first means responsive to radiant heat, dry bulb temperature and wet bulb temperature, said control means including an adjusting means whereby the inside effective temperature may be maintained at a prededarkened so as to absorb radiant heat, a low volt- ,most button 68, the rod I 9 indicates 70 degrees. 1 In other words, when the outdoor dry bulb temrelationship between the indoor effective temperature and the outdoor temperature.

It is apparent, therefore, that I have devised an air conditioning system that functions in a new and improved manner. The control for the system is simple and requires no expert care or v x the claims which follow.

What is claimed is as follows:

1. In an air conditioning system, an evaporator, refrigerant liquefying means in refrigerant flow relationship with said evaporator, means for circulating air to be conditioned over said evaporator, and control means for said liquefying means comprising a wet and dry bulb temperature responsive element in which the dry bulb has been darkened so as to absorb radiantheat.

2. In an air conditioning system, an evaporator, refrigerant liquefying means in refrigerant flow relationship with said evaporator, means for circulating air to be conditioned over said evaporator, and control means for controlling said liquefying means in accordance with effective temperature conditions, said control means including a manual adjusting means cooperating with a scale calibrated in terms of outside temperatures whereby said control means may be set at an effective temperature which is proportional to the outside temperature.

3. In combination, means for cooling and dehumidifying air for an enclosure, and control means for said first means responsive to radiant heat, dry bulb temperature and wet bulb temperature.

.age circuit, means whereby said temperature responsive element closes said low voltage circuit at a predetermined effective temperature, and means whereby said low voltage circuit controls said refrigerant liquefyin means.

6. In an air conditioning system, an evaporator, refrigerant liquefying means in refrigerant fiow relationship with said evaporator, means for circulating air to be conditioned over said evaporator, and means responsive to radiant heat, moisture'and temperature for starting and stopping said refrigerant liquefying means.

'7. In combination with refrigerating apparatus, a capillary tube having an enlarged portion charged with mercury, wick means covering one section of said enlarged portion, radiant heat absorbing means covering. another section of said enlarged portion, spaced contacts within said tube adapted to be bridged by said mercury at a predetermined effective temperature, a source of current and a relay in series with said contacts, and means whereby said relay starts and stops said refrigerating apparatus.

8. In an air conditioning system, an evaporator, a condenser, a compressor, refrigerant flow means between said evaporator, condenser and compressor, a motor for operating said compressor, control means for said motor, said control means comprising a capillary tube having an enlarged portion charged with mercury, wick means covering one section of said enlarged portion, radiant heat absorbing means-covering another section of said enlarged portion, spaced contacts within said tube adapted to be bridged by said mercury at a predetermined efiective' temperature, and means whereby said motor is caused to operate when said spaced contacts are bridged by said mercury. 1

9. In an air conditioning system, an evaporator, a refrigerant liquefying means for supplying 10. In combination, an evaporator for cooling a body of air for an enclosure, refrigerant liquefying means in refrigerant flow relationship with said evaporator, and thermostatic means for controlling the removal of heat from said body of air by said evaporator, said control means including a manual adjusting means cooperating with a. a

scale calibrated in terms indicative of the thermal condition of the air outside said enclosure whereby said control means may be adjusted to the zone on the calibrated scale indicative of the thermal condition of the air outside said enclosure.

11. A device of the character described comprising a capillary tube having means for closing one end, a pair of interconnected bulb portions of which one is connected to the remaining end of said capillary tube, said pair of interconnected bulb portions being filled with thermally sensitive liquid and a column of thermally sensitive liquid extending into said capillary tube, a wick surrounding one of said bulb portions, and means for supplying moisture to said wick.

NELSON J. SMITH. 

